Known from the publication DE 103 05 241 A1 is a 6-speed or 7-speed dual clutch transmission. The dual clutch transmission comprises two clutches, each linked with their inputs to the drive shaft and each with their output to a respective one of the two transmission input shafts. The two transmission input shafts are coaxially positioned with each other. In addition, two countershafts are positioned axially parallel to the transmission input shafts, their idler gears meshing with the fixed gears of the transmission input shafts. Furthermore, coupling devices, that are axially movable, are connected in a rotationally fixed manner to the countershaft to shift the respective gear wheels. Each selected ratio is transferred by the drive gear wheels to a differential transmission. To achieve the desired gear ratio steps in this known dual clutch transmission, a vast number of wheel planes are required, so that a significant amount of installation space is needed.
In addition, a spur gear variable-speed transmission is known through the publication DE 38 22 330 A1. The spur gear variable-speed transmission comprises a dual clutch, switchable under load, where one part is linked with a drive input shaft and the other part with a hollow drive shaft, positioned rotatable on the drive input shaft. For certain gear ratios, the drive input shaft can be coupled with the hollow drive shaft through a shifting device.
Known from the publication DE 10 2004 001 961 A1 is a power transmission with two clutches, each of which are assigned to a partial transmission. The transmission input shafts of the two partial transmissions are positioned coaxial to each other and mesh, via fixed gear wheels, with idler gears of the designated countershaft. The respective idler gears of the countershafts can be connected in a rotationally fixed manner with the respective countershaft by designated shifting devices. The particular idle wheels of the countershaft can be connected in a rotationally fixed manner via the assigned shifting devices with the associated countershaft. A 7-gear transmission, among other things, is known from this publication in which an additional shift element is provided to link the two transmissions input shafts to establish an additional transmission stage. The 7-gear transmission requires in this embodiment at least six wheel planes in the two partial transmissions, to achieve the transmission stages. This causes an unwanted extension of the construction length in the axial direction, thereby significantly limiting use in a motor vehicle.